I've been looking over this, and haven't seen anything wrong in my procedure.
Take 2468 *3162
[Using Karatsuba multiplication]:
x=2468
y=3162
x={(a)24}{(b)68}
y={(c)31}{(d)62}
Step 1: a*c=(24)(31)=744
Step 2: b*d=(68)(62)=4216
Step 3:(24+68)(31+62)=8556
Step 4: 8556-4216-744=3596
Step 5:
7440000+4216+3596000=11,040,216
However 3162*2468=7,803,816
I've looked over this . I am using even digit numbers. Let me know what needs to be done to this to get the right answer.